TULSA, Oklahoma - An exclusive News On 6 poll shows the race to replace First District Congressman Jim Bridenstine in the Republican runoff is still wide open.

In a Sooner Poll survey of more than 800 likely Republican voters, 37.5-percent support former Tulsa County District Attorney Tim Harris and 26-percent support businessman Kevin Hern.

More than 36 percent say they're undecided.

"Harris is doing best among those who really matter the most -- those over the age of 65, those high-propensity voters that will naturally turn themselves out and also in Tulsa County, which Tulsa County makes up 76 percent of that first congressional district," said Bill Shapard, Sooner Poll.

The runoff election is Tuesday, August 28th.